ITunes INCREDIBLY slow since library transfer to Mac

Question

Hi all
Specs upfront:
Mac Mini PowerPC 1.5gig
Tiger with latest updates10.4.7
Bluetooth Apple Wireless Keyboard and Bluetooth Apple Wireless Mouse Pro
brand new Newertech ministack 500gb drive and later upgrade to 1gig memory (explained below)
My problem is that iTunes has been running INCREDIBLY slowly since I moved my library yesterday. Allow me to give some backstory.....
I purchased the mac mini last winter, and I have a large music collection that would not completely fit onto the mini hard drive at that time (approx. 330 gig - >73,000 files) - so what I did was get a crossover cable and networked my mac to my pc and would access my music files on my Windows iTunes library via the "shared library via network" option. It worked fine. I couldn't update track information nor change artwork as needed, but I could at least access my music, and it would do it at a fairly fast clip. When I first would select the Windows iTunes library the beach ball would spin for about a minute, presumably to load in the library informationfrom the PC, but then I could search change tracks, etc, with relative ease and spriteness. Additionally I could do other things on the mac (mostly just goof on the internet and check email, but occassionally do higher function tasks like edit photos in iPhoto or Photoshop elements.) Again, all without any problem.
So last week I took advantage of a sale online of the Newertech ministack drives, and bought a 500gb model. Via the crossover cable I transferred all the music files to the new external hard drive (which is either firewire or USB, my choice) - I accomplished this by making the library folders on the XP sharable, clicked "add to library" on the mac and chose the music folders on the XP, but then had the mac automatically copy the files to the Mac library and also set the Mac itunes to keep the library organized. This took quite a long time - probably close to 20 hours or so. I lost playcounts and the dates things were added, but I figured what the heck. Clean start on a new machine. And also figured that I would figure out a way to get that information moved eventually anyway.
This is when the problem started - and the source of my quandry that I'm hoping someone will be able to help me with.
When I first start iTunes it take a LONG time (about 3 miuntes) to load up - but then again, no problem as I figure it is reading the xml file. HOWEVER< When i now select a song, it will take a few seconds to begin to play, but then what's more odd it that it just about pulls my system down completely. And this is only using iTunes, and perhaps being online (via telephone line) - no other processor or memory intensive thing going on. Switching through songs is a nightmare, and has rendered the entire system non responsive at times forcing a restart.
Furthermore, when it will switch from one song to the other, the information window in itunes (that shows the songs, time elapsed etc) will hang - the next song will already be playing, but the old information will be there hanging - and then the information will "jump" to the current track (usually about 30-45 sconds into it) , but oftentimes I will get the spinning beach ball, as well as itunes not responding at all. Music stutters or cuts out completely for a few seconds. There have been times I've attempted to change information on the ID3 tag through itunes, but clicking the get information button has sometimes resulted in the dialogue box for said track not coming up until the next track is playing because of the beach ball spinning.
I went out and bought 1 gig of RAM for the machine (the max this model can take) and it has MOSTLY stopped the stuttering of the music as it plays (I was watching istat nano, and would notice when a track played my RAM would slowly go down from approx 200 meg free to about 5 meg free, and then the stuttering would begin) - installing the extra memory has stopped this mostly as I said although in watching the istat nano there is a significant chunk of memory being used during the first part of any song before it jumps back to less memory being used). From what I can tell however, it doesn't use up much CPU cycles (using istat nano)
What I find most aggrivating about this, is that when I NOW choose the shared playlist from my XP - it STILL works great as it did before. I can click through, have the computer play songs randomly, do search queues as before and it operates without a hitch, and those hard drives are on a different machine on the floor. Mind you I can't change any information on those tracks, but I can hear and search and change through songs, play, pause responds immediately no problems..........But when I switch back to the "local" mac library eveything goes to **** again. A few times iTunes has completely stopped responding, resulting in me having to force quit the appication.
So having said all that (and if you are still reading this, thank you - I know it is long windeed but figure too much information is better than just my saying "it's not working, how do I fix it" ) I understand that this is a rather large music file (used at my place of employment, I had the guys I work with add their music to it, and use it as a library for the workplace) but I'm sure also that there are others out there with much larger music collections who are doing this without a hitch.
What I HAVE tried so far is to repair the permissions (which were only on the internal Mac drive - no permissions were on the external drive according the the Utilities as that option was greyed out - is that normal? I'm still new to macintosh and have no idea what permissions are, other than people with similar problems as mine on the board were reccommended this as a potential remedy) - and of course I doubled my RAM as described earlier. When I installed the new memory I zapped the PRAM (two chimes on startup) and when I check system preferences the extra memory is showing as available. I even defragged the internal drive thinking that might help, but to no avail. I attempted running the hard drive using the firewire connection and then attempted the USB connection, again, with no luck.
It is most frustrating in that I was looking forward to FINALLY having everything on my Macintosh properly and all things running smoothly - but so far it has just been an aggrivation and has had me scratching my head wondering if I should just have left well enough alone and always have the Mac networked with the Windows machine, or even just stuck with the Windows machine ....... :: shudders ::
Should I delete the xml file and have iTunes rebuild it? Or should I uninstall iTunes and reinsall it? If so, on the internal drive, or on the external drive (provided I can even do that) - as I said before I have no favorite tracks or playlists on the mac yet, so I'd be losing nothing in trying it, and would gladly welcome anything that would resolve this.
I hope you can help, and I anxiously await your response which could be the soluton to my problem.
Respectfully submitted,
Len

Answer 1

Mac OS doesn't use drive letters.
There are instructions to move iTunes to anew computer here: http://support.apple.com/kb/ht4527